Alloy with copper as primary metal



' vention which distinguishes it from the prior,

Patented Sept. 6, 1932 GEORG PEIETZRIEDER, OF BERLIN-TEIIPELHOF, GERMANY ALLOY WITH. COPPER AS PRIMARY METAL Io Drawing. Application ma May 1, 1921,

Many attempts have been made to produce lead alloys especiall adapted for bearing metal by adding other materials to lead. Such an alloy must answer the physical and mechanical requirements demanded by this use in the highest possible degree; that is to say, it must have sufiicient hardness, good lasticity, high compressive strength, and avorable gli ing qualities.

In German Patents 420,068 and 423,292

refining lead this method, consisting in is departed from,

addition of other materials,

and instead, expensive alloys, such as bronze,

are spread or diluted by the addition of lead. 1)

The alkali metal content causes a good dis- At the same time there are added to the copper and tin, in addition to a maximum of about 25% of lead, small percentages of nickel andzinc. In German Patent 436,440 bronze is again the base metal and, beside lead and tin, zinc, vanadium, and refractory metals are added to improve the alloy.

The essential novel idea of the present inart is the spreading of an alloy having copper as a base metal by the addition of lead refined by the addition of alkali metals.

Heretofore tin-bronzes with proportions of lead varying within wide limits have been found to be adapted for many difierent purposes. 'The usefulness of these bronzes is greatly increased by raising their lead content with the accompanying increase in plasticity, on theother hand the proportion of lead which can be added is influenced to a great extent by its qualities. The lead added to the bronze base alloy is only taken up in solid solution to a slight degree. Most of the lead separates in the form of small drops and thereby becomes a determining factor of the alloy.

Pure lead has very little hardness (Brinell hardness about 3.6 to 3.8 kg. per sq. mm.)

and is for this reason not well adapted for bearing metal, for, example. It has a tendency to smear, due to its very low strength, and is therefore the frequent cause of failures of full leaded axle boxes of bronze alloys having a high proportion of lead. For this reason, up to this time an admixture of 15 Serial No. 534,449, and in Germany Kay 2,

- example.

.ments have shown,

to 20% lead in the alloy has been found to be the optimum limit. I

According to the present invention instead of pure lead there are used hardened lead alloys, which practice has shown to be exceptionally good for bearing purposes, for

These hardened lead alloys (Brinell hardness 30-45 kg. per'sq. mm. can be very easily. produced from pure lea by the addition of alkali or alkaline earth metals, and can be brought into the alloys having copper as a base metal without difiiculty. These base alloys may consist of pure coper-tin, or may have zinc as an added metal. persion of the hardened lead alloy in the bronze and the siderably repressed. This is an important technical improvement in alloys. Experithat in such an alloy increased hardness, superior compressive strength with good plasticity, used as bearing metal, for example, very favorable gliding qualities are attained.

In the following tables a lead bronze as previously used and one composed in accordance with the inventlon are compared:

5860 kg. per sq. cm. 3450 kg. per sq. em.

Brinell hardness 49-50 kg. per sq. cm. Effective compressive strength 2750 kg. per

sq. cm. Reduction 45% Tests of alloys in accordance withthe invention have shown that its wear is particularly low and the troublesome smearing which occurs with previously used alloys is prevented.

Accordi to the invention a certain percentage of zinc also may be added to the primary alloy. In the following table there is given another comparison of an alloy used heretofore and one in accordance with the invention.

troublesome liquation is con-.

and, when 2 p iteaaaea Lead bronze Bronze according to the invention 63-47% Cu 62.8 -46.2% Cu 4-8 Sn 4 8 Sn 340% Zn 3 10 Zn 30-36% Pb 30 35 Pb 0.10- 0.5% alkaline earth 0.10- 0.3% N a The alloy according to the invention is-dis- 1o tinguished further by a greater mechanical solidity.

A small percentage of nickel can be added also to the alloy to obtain greater homogeneity. The alloy can be made up by adding the hardened lead alloy to the base alloy in solid or liquid state with simultaneous thorough mixing, or it can be made by mixing all the alloying elements together in the manner -described.

' Having described my invention, I claim:

1. An alloy composed of the following ingredients in approximately the proportions given: copper 62.3% to 46.2%, tin 4 to 8%, zinc 3 to 10%, lead to alkaline earth metal 0.2 to 0.5%, and sodium 0.1 to 0.3%.

2. A lead bronze alloy containing about to 8% of tin, about 3 to 10% zinc, about 2 to 35% of lead, about 0.1 to 1% of one or more 30 metals selected'from the alkali and'alkaline earth group, the remainder principally coper. 3. A bearing composed of the alloy described in claim 2. 35 4. A lead bronze alloy containing about 5% of tin, 3 to 10% of zinc, about 24.5% of lead, about 0.1 to 0.2% of one or more metals selected from the alkali and alkaline earth group, the remainder principally copper.

4o 5. A bearing composed of the alloy. de-

scribed in claim 4. 6. A lead bronze alloy'having the composition stated in claim 2 and containing in addition a small percentage of nickel to improve *5 the homogeneity.

7. A bearing omposed of a lead bronze alloy having the omposition stated in claim 2 and containing in addition a small percentage of nickel to produce greater homogeneity. In testimony where I afiix my signature.

GEORG PEMETZRIEDER. 

